argument got ignored in CMD in Dockerfile - r

Question

I have a dockerfile as below
but when i run it and check logs, it says, "ARGUMENT 'plumber_2.R' ignored". I have tried with diffrent ports as well.
I have tried with different ports but failed
FROM r-base:3.5.1
# Install Ubuntu packages
RUN apt-get update && apt-get install -y \
sudo \
gdebi-core \
pandoc \
pandoc-citeproc \
libcurl4-gnutls-dev \
libcairo2-dev/unstable \
libxt-dev \
libssl-dev
## RUN R -e 'install.packages(c("devtools"))'
## RUN R -e 'devtools::install_github("trestletech/plumber")'
#
RUN install2.r plumber
RUN R -e "install.packages(c('MLmetrics','datasets','tsDyn','ggplot2','zoo','forecast'), repos='http://cran.rstudio.com/')"
WORKDIR /usr/plumberR
COPY . /usr/plumberR
RUN sudo apt-get install curl
EXPOSE 8000
ENTRYPOINT ["R", "-e", "pr <- plumber::plumb(commandArgs()[4]); pr$run(host='0.0.0.0', port=8000)"]
CMD ["plumber_2.R"]
expected is the output but I am getting "ARGUMENT ["plumbr_2.R"] __ignored__

Answer 1

Your third ENTRYPOINT argument breaks the sequence. It should be taken in additional quotes, but unfortunately you use single quotes internally for host specification.
Option 1
If you dont plan to override CMD in your future calls to docker run, you can avoid JSON schema in ENTRYPOINT/CMD and use something like:
ENTRYPOINT R -e pr <- plumber::plumb(commandArgs()[4]); pr$run(host='0.0.0.0', port=8000) plumber_2
Option 2
Put 3rd argument in single quotes and somehow avoid useing them for hot specification:
"'pr <- plumber::plumb(commandArgs()[4]); pr$run(port=8000)'"